Field of the Invention
The present invention relates to a wafer processing method for dividing a wafer into a plurality of individual device chips along a plurality of crossing division lines and covering each device chip with a resin, the division lines being formed on the front side of the wafer to thereby define a plurality of separate regions where a plurality of devices corresponding to the device chips are each formed.
Description of the Related Art
In a semiconductor device fabrication process, a plurality of crossing division lines are formed on the front side of a substantially disk-shaped semiconductor wafer to thereby define a plurality of separate regions where a plurality of devices such as integrated circuits (ICs) and large-scale integration (LSI) circuits are each formed. These regions are divided from each other by cutting the semiconductor wafer along the division lines, thereby producing a plurality of individual device chips each corresponding to the devices.
In recent years, there have been developed packaging techniques of dividing a wafer into individual device chips and covering each device chip with a resin. A packaging technique called wafer level chip size package (WLCSP) as one of the above-mentioned packaging techniques is disclosed in Japanese Patent Laid-open No. 2006-100535.
The packaging technique disclosed in Japanese Patent Laid-open No. 2006-100535 includes the steps of covering the back side of a wafer with a resin, forming a cut groove on the front side of the wafer along each division line, the cut groove having a depth reaching the resin covering the back side of the wafer, applying a mold resin to the front side of the wafer to cover each device with the mold resin and fill each cut groove with the mold resin, and cutting the mold resin filling each cut groove by using a cutting blade having a thickness smaller than the width of each cut groove, thereby dividing the wafer into individual WLCSPs.
Further, as a wafer processing method for manufacturing such WLCSPs, the following technique has been developed.    (1) A cut groove having a depth corresponding to the finished thickness of each device chip is formed on the front side of a wafer along each division line.    (2) A mold resin is applied to the front side of the wafer so as to fully cover the front side of the wafer with the mold resin and fill each cut groove with the mold resin.    (3) A protective member is attached to the front side of the mold resin covering the front side of the wafer, and the back side of the wafer is next ground to expose the bottom of each cut groove to the back side of the wafer.    (4) A dicing tape is attached to the back side of the wafer, and the mold resin filling each cut groove is cut by using a cutting blade having a thickness smaller than the width of each cut groove, thereby dividing the wafer into individual WLCSPs.